I would like to see this question answered. (Not the pirate part - you should buy the game.)
I also prefer to play private games with friends and not involve any gaming/matching service. I have no interest in playing with strangers, no interest in stats, etc. I also prefer to not deal with the extra menus and the idiots spamming the lobby.
My friends and I all have legal purchased copies. We have played both on ICO and LAN and Hamachi. When playing on Hamachi, the game always get out of sync. Ports are open and allowed, but there is obviously something else needing to communicate that is not happening.
LAN seems to work with no issues. Only 1 partial game on ICO, so we don't know if desync happened yet. Hamachi works fine for other games and have used it for a long time. I do not suspect Hamachi at this time. In Hamachi, remote Hamachi users are unable to see the LAN game of SINS, but can join if type in Hamachi IP. Game always desyncs.
TCP 6112 and 6000 are both allowed and forwarded. Any other ports that are required for the game or not documented so far?
Also - how do you disable ALLOY? I have never seen it listed as an option.